1. Technical Field
The present invention relates to a technology for expressing gradation using a so-called frame rate control (FRC) method in display devices.
2. Related Art
There has been known the FRC technology in order to make a light modulation element capable of expressing only a low number of gray levels display an image with a higher number of gray levels (e.g., JP-A-2007-178509 (Document 1) and JP-A-2013-222048 (Document 2)). The FRC is a technology of time-dividing an image to modulate the gray levels on the time axis to thereby increase the number of gray levels available for expression. For example, in the case of modulating an image using four frames in the light modulation element capable of 8-bit (256-gray level) expression, 10-bit (1024-gray level) expression is achievable.
In the technologies described in Document 1 or Document 2, the modulation fails to be applied to some pixels in which the lower bits of the input data correspond to a specific bit sequence (e.g., pixels with the low 2 bits of “00” in the example described above). In this case, there is a problem that if the pixel to which the modulation by the FRC is applied and the pixel to which the modulation by the FRC is not applied are adjacent to each other, the boundary is visually recognized in some cases.